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Oh yesssssss I was searching high and low for this thread
Original post by Nabihah
This is a thread for the F325 exam as I havent seen one yet. Has anyone else started learning for this exam as my college started teaching F325 first. We can post questions and revise on this thread.


How are you finding it? We have almost finished :smile:
Reply 4
Original post by letsbehonest
How are you finding it? We have almost finished :smile:

Not too bad to be honest, but we've just finished enthalpy and entropy and still have a whole section left. I think we'll finish in January
Reply 5
Do any of you guys do OCR?
Original post by Nabihah
Not too bad to be honest, but we've just finished enthalpy and entropy and still have a whole section left. I think we'll finish in January


That's great! I don't think it is too bad tbh. I hate organic chem though - unit 4 is going to be so boring. I can sense it already
Reply 7
Original post by blairxoxo
Do any of you guys do OCR?

Yes, this is the thread for OCR
Reply 8
Original post by Nabihah
Yes, this is the thread for OCR


cool x
Acids and buffer questions are annoying.
Or is it just me?

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Reply 10
Has anyone got the f325 June 2013 paper? I need it ASAP!
Reply 11
We're finishing cells I think and then starting acids and buffers but it's all very choppy changey at the min.. Like we jumped to carbonyls (unit 4) and then back to unit 5


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Reply 12
Original post by Uhassan123
Has anyone got the f325 June 2013 paper? I need it ASAP!


Bump
Reply 13
Hey Guys, hows revision coming along? Can anyone explain how you draw those titration curves, and how you decide on using a suitable indicator and so on? Im so confused, I can work out the pH of the acid and alkali but how do you work out the equivalence point and the volume? Its so confusing, any help would be great, thanks :smile:
Reply 14
Has anyone got a copy of the F325 June 2013 paper??
Reply 15
Original post by tee_bs
Hey Guys, hows revision coming along? Can anyone explain how you draw those titration curves, and how you decide on using a suitable indicator and so on? Im so confused, I can work out the pH of the acid and alkali but how do you work out the equivalence point and the volume? Its so confusing, any help would be great, thanks :smile:


Hi :biggrin:, think of the titration curves as 4 different types, so you have the
strong acid
vs strong alkali
strong acid vs weak alkali
weak acid vs strong alkali
weak acid vs weak alkali

now for the first example you have a strong acid, so a good example would be HCl (strong acids will have pH close to 1) and a strong alkali such as NaOH (strong alkali would level off at a pH of about 13.5)
so when you actually draw this on a graph it would have a line coming out of pH at around 1 and slowly rising, and when reached at 25cm3 there will be a dramatic increase in pH, this is called the end-point its where there is a colour change. what happens is that you have a solution of HCl and you titrate it by adding NaOH, when most all all HCl have reacted there will be a colour change.

because this is a strong alkali the graph would level off at pH of around 13.5
the equivalence point is when H+ = OH- t
by using certain indicators we are able to figure out the pH, in the exams they give you 3 examples of indicators with pH range and ask you to conclude which indicator will be used, and by looking at the around the equivalence point you are able to see which indicator you will use...
let me explain:
strong acid vs strong alkali will give you a pH of 7 (the equivalence point)
what i do to help me out is mark a line at the start of the increase.. so at 25cm3 there will be an increase and at the start of that increase i will put a mark, next i will put a mark just about where it levels off, and then from those 2 i will add a middle line, and try to get a reading from that, but the best way of learning it, is by understanding the pH levels you will get for the different types of titration curves.

well i hope i helped, all the other types follow the same rule but the shapes would be different and i believe you have examples in your book or so, if you don't let me know and i will try to explain to you.
if i missed anything out let me know
Reply 16
This exam is so hard to revise for It's all about practice.
Reply 17
has anyone got the f325 paper and mark scheme? ran out of past papers!
Reply 18
Hi guys, I'm preparing for my F325 exam and I am stuck on this question (calculating pH) could someone please go through this with me step by step? I get part (i) but the part (ii) i can't do - even calculating the moles of NaOH! I would appreciate any help
Reply 19
Original post by kajagoogoo
has anyone got the f325 paper and mark scheme? ran out of past papers!


If you've done all the recent papers then you can do the old spec papers, which are really good practice